FROMLIST: tracing: add flag to control different traces

More traces like event trace or trace marker will be supported.
Add flag for difference traces, so that they can be controlled
separately. Move current function trace to it's own flag
instead of global ftrace enable flag.

Bug: 160464759
Link: https://lore.kernel.org/patchwork/cover/1280618/


Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Change-Id: I25f9fd4d3af7a82e013f6855e8ca69066b371cff